THE STUDY OF THE EVOLUTION OF THE FLOWEE. 245 



one or a few characters may not prove of much importance, hut when the action of 

 evolutionary forces has achieved a like resultant or effect, and similar comhinations 

 of characters are found, the prohlem of origins hecomes almost insoluble. 



The author is led, from the facts presented here, to express the strong conviction that 

 the structural peculiarities to he perceived in both the Caprifoliaceae and Cornacese are 

 indicative of different origins ; that certain genera in each family have pursued inde- 

 pendent hut similar lines of development, and hence both families are convergent and 

 polyphyletic. The case for the polyphyletic origin of Cornacese has already been stated 

 before the Botanical Section of the British Association at Portsmouth in 1911 *. 



The author, in conclusion, indicates the bearing of modern experimental work upon 

 the field of enquiry pursued here, discusses the affinities of the three families specially 

 studied, outlines the general features in the evolution of the floral vascular system and 

 of the ovule, and, finally, sums up the position created by this investigation in relation 

 to the natural classification of Angiosperms. 



This research was commenced at the Boyal College of Science, London, and finished 

 at the Wisley Laboratory, and my thanks are due to the President and Council of the 

 Eoyal Horticultural Society and the Director of the Laboratory for the opportunities 

 they have given me for pursuing my study on this subject at Wisley. 



I am chiefly indebted to Professor J. B. Parmer, P.B.S., and to Mr. A. W. Hill, P.L.S., 

 Assistant Director of the Eoyal Botanic Gardens, Kew, for the material used. 

 Specimens of Griselinia lucida were kindly collected and preserved for the purpose 

 of this investigation by Miss Heywood, in New Zealand, at the request of Dr. 0. 

 V. Darbishire; and flowers of Griselinia littoralis were contributed by Mr. J. 

 W. Hamilton of Hamwood, Dunboyne, Ireland. Por the rare female catkins of Garrya 

 elliptica, the author is indebted to Messrs. Yeitch, and inflorescences of several 

 rare CaprifoliacejB were obtained from the Gardens of the Boyal Horticultural Society. 



2. HAMAMELIDACEiB. 



Since the writer aims at a comparison of origins, considerable importance is attached 

 to details of floral organization, and for this reason special attention is given to variability 

 in the position occupied by the ovary in relation to the remaining floral whorls to details 

 in the internal structure of the ovary, to the number and structure of the ovu es, and to 

 steriHzation in the ovary ; special interest also attaches to an mstoce of the trans- 

 formation of the petals into stamens that he has observed in Corylopm and to the 

 elucidation of the morphology of the bracts found in Farrotia, whilst the course of 

 the vascular tissue in the flower has also been traced. ^ . i 



The variability in the position occupied by the ovary in relation to the out^r whorls 

 will be considered first. Distylium is hypogynous, Uammnelis and Corylopsjs^ are 

 perigynous, and the perianth and stamens are seated upon a circular r 

 attached to the ovary below mid-height. TAchocladus also is perigynous, but the ndg 



dge of 



« 



A. S. Home in Proc. Brit. Assoc. Adr. Scl. Portamoutli (1911), p. 585. 



